Docker: only commit to image if service URL returns HTTP code 200 (OK)

Docker: only commit to image if service URL returns HTTP code 200 (OK)

Safe backup image overwriting #2

With docker, there are several ways to backup your data or entire containers; one of those ways is to commit to an image, which can later be used to fire a container with the exact same contents the source container had when that image was created.

But if for some reason the container gone bad, you don't want to overwrite that image with its contents. If this is a service with a HTTP endpoint, one way is to check if its base URL returns HTTP code 200 (OK); if it does, everything is ok and we can go ahead and replace last image with current contents one:

#!/bin/bash
ret=$(curl -I -s "$2" -o /dev/null -w "%{http_code}\n")
((ret==200)) && docker commit $1 $1_fb

In  this case, I'm creating an image with the name of the running container plus a "_fb" suffix to identify that it's the one with my contents.

Call it via

./<script name>.sh <container name or id> <base URL>

If you want to make some basic clean-up, delete the untagged images by adding to the script

docker rmi $(docker images -a | grep "^<none>" | awk '{print $3}')

Enjoy!